Have you been calling yourself names again? Imagine telling a friend or child that they are fat or stupid or incapable. Not likely, yet the harsh parent within you may feel quite free to beat up on you, on your inner child. Your conscious, active mind hardly notices these attacks, especially if they've been ongoing. But hearing bad things about yourself on a regular basis is undermining. The next time you make a mistake or don't live up to expectations, pay attention to what you do and say to yourself.
Self-attack can be painful enough that you may alleviate the pain by turning it outward. Your scolding parent makes your inner child want to protect itself and, as children do, you look for someone to blame. Now you have a mess. You hate yourself, hate someone or something outside of yourself and are moving away from the truth of what actually happened.
I'm not a fan of positive self-reinforcement in the form of untrue messages. You're not the best, at least not for any extended time. Rather than pumping yourself up artificially, I think it's better to raise your awareness and gradually get rid of the name calling and harsh criticism; getting to the point where you can speak the truth without being mean about it.
I also like creating a few messages that have the voice of a good parent,i.e., supportive and directive. I have two that are simple but work for me.
"I'm doing the best I can." Saying this is reassuring and true. Being able to take in the message alleviates the anxiety that goes with pushing oneself when nothing more can be accomplished. That doesn't mean I've accomplished a great deal. Maybe I'm having a 20% day as compared to 100% day but that's OK. My message is about me, not a task.
My second message is quite opposite of the above.I dislike the state of procrastination though I can dwell there. I'm as good as anyone at putting ice cream or a nap between me and a task. But I'm uneasy, aware of working at being distracted. It all gets better when my good parent shows up and says, "Try harder". Once heard, the procrastination is acknowledged and it's difficult to settle back into sloth. It's a kind message because it says "try". It allows me to say, "OK, I'll try a little bit". Almost always, that little bit gets me going. I don't mix my two messages. If I'm doing my best,I don't tell myself to try harder.
I stumbled on these good parent messages that work for me. Best of luck in finding yours. And, by the way, you don't have to have had good parents to find a good parent within yourself.